The woman’s skin was almost transparent. Her light hair darkened at the tips. Her lips were blue and slightly parted. But all Mackenzie could focus on were the eyes. Those arctic eyes that looked glassy like glistening marbles. She could see her own reflection in them staring back at her. The woman looked almost like a carefully crafted doll.

Detective Mackenzie Price knows what makes a killer tick. But when she finds the body of a young woman dumped in the trunk of her car, she knows this case is going to be the most personal and twisted yet.

Looking down at the victim, Mack recognizes her instantly: Sophie Fields, the fiancée of Mack’s coworker who vanished months before. Reeling in shock, Mack keeps one crucial piece of evidence to herself, too horrified to share it: a crumpled piece of paper bearing the words “You’re welcome, Mackenzie”.

As Mack pieces together Sophie’s last known movements, another body is found with a note. This time the victim is Courtney Montenegro, Mack’s childhood bully. As Mack looks at the note, it becomes clear that the killer has an unusual MO: They want to protect her at all costs. But why?

The only evidence connecting the victims are identical pieces of material left at both crime scenes. With no other leads, Mack unearths a cold case that may lead her to the killer. Sophie had a sister who disappeared years before. Did she get too close to the truth and pay the ultimate price?

With an obsessive killer still on the loose, Mack knows that she needs to get deep inside their mind to work out who is next on the hit list. Can she get to the killer in time before someone close to her loses their life?